Single-walled carbon nanotubes (SWNTs) have become one of the most intensely studied nanostructures because of their unique properties. The inherent physical properties of carbon nanotubes make them ideal supports for metal nanoparticles. The use of electrodeposition to modify SWNTs in order to facilitate applications in areas related to catalysis and sensing is presented in this manuscript. Preparation of raw SWNT material for electrochemical experiments involves various mild or oxidative pretreatments. In this review we focus on progress toward functionalization of SWNTs with metal nanoparticles using electrochemical methods and the applications of metal decorated carbon nanotubes in energy related applications.